Heretofore, many different types of machines and methods for cleaning carpets have been proposed. Some of the more basic types are the rotary brushwet shampoo machine and method such as shown in U.S. Pat. No. 3,728,075 wherein a mop head is utilized as a pad and rotated over a wetted area of the carpet to shampoo the pile. The absorbent material of the mop head soaks up the soiled liquid detergent. However, this method often causes severe pile distortion and flaring of tufts and tends to clean only one side of the fibers in a pile due to the single rotary motion of the brush. Vacuuming is used to remove the shampoo and soil after shampooing but such methods are largely ineffective.
Other types of machines and methods utilize a cylindrical brush which scrubs the carpet pile. While such a machine does have a built-in vacuum to remove the shampoo and dirt following scrubbing, residue is often left in the carpet. The action of the rotating cylindrical brush often causes severe pile distortion and flaring of tufts and provides less cleaning than other techniques. Another type of machine and method is the vibrating plate machine which gives a cleaning action such as shown in U.S. Pat. No. 3,655,444 wherein a sheet of elastic material having a surface which is embossed or otherwise treated to be irregular is carried by a vibrating drive plate. The plastic scrub surface scrubs or agitates the carpet pile either during or after the pile has been wetted with a detergent solution. This method produces little pile distortion and flaring during cleaning, however, less cleaning is incurred than in the above methods and there is no means for removal of shampoo and soil except by subsequent vacuuming.
All of the above methods which utilize application of a shampoo or cleaning solution have the disadvantage that the carpet pile is directly and often over-wetted to the point of causing damage and requires an additional removal step of vacuuming or a prolonged drying period before use. The machinery utilized is quite heavy which limits the use and the type of person who can operate such a machine. Typically, such machines have been too heavy and unwieldy for housewives or female custodians to use.